An iframe loaded with custome scheme cannot invoke host methods

[1339240789]

Description

I have a web page that loads using a custom scheme, it can call the host method normally, but the iframe inside cannot call the host method

Version
SDK: 1.0.1901.177
Runtime: 115.0.1901.203
Framework: Winforms
OS: Win11

Regression
Was this working before but has regressed?
If yes, what version did this last work on?

Repro Steps

Screenshots

Additional context

[1339240789]

Instead of using a custom scheme, I tried to use the file protocol to load the main web page, where the iframe would normally call the host method